Process of making phosphoric acid



Patented Nov. 30, 1926.

UNITED STATES PATENT HENRY BLUMENIBERG, 33., OF- LOS ANGELES,

OFFICE.

canmonnm, .assrenon 'ro scrocx- HOLDERS SYNDICATE, 01 LOS ANGELES,CALIFORNIA, A. CORPORATION OF CAIII- FORNIA.

rnocnss or name rno srnonrc ACID.

No Drawing.

My invention relates to a process of n iak eing phos horic acid, andhasfor'its object to'provi e a simple, efiicient-and economic process ofmaking phosphoric acid, using as 5 the principal agent, sul hur dioxide.

The same consists in t e steps of the proces's hereinafter described andclaimed.

Crude phosphate rock- Oa,(PO,), is ground to suitable fineness, such as100 mesh, and mixed with water in sulphur dioxide. For example, 100parts by weight of water, are added to 10 parts of pulverized phosphaterock, and the mixture is saturated by any suitable means with sulphurdioxide. The sulphur dioxide in the presence of'water will formsulphurous acid. Within twenty-four hours the following chemicalreactions will takeplace, as indicated.

It is well known that calcium phosphates '2 are more or less soluble insulphurous acid,

but the novel feature of my process consists in maintaining the sulphurdioxide in excess in the mixture, so that the phosphoric acid liberatedis prevented from re-acting on the a calcium sulphiteformed.

liberated from the calcium ion, the reaction the presence of Applicationfiled April 30, 1826. Serial 110. 27,086.

takfi place as indicated in the chemical equations above stated. y

In processes of the prior artuthe calcium phosp' ate is mixed with'soluti ons of sulphurous acid in water, and the phos hate rock re-actswith the sulphurous aci f becoming neutralized and forming abemi-calciumdi-hydrogen phosphate and calcium 4. sulphite. 1

My new process prevents this reversion by keeping the mixture underpressure and with the sulphur dioxide in excess, so that at .the momentthe insoluble calcium sulphite is formed the liberated PO radicle cannotre-act on the calcium sulphite' as'the S0, at ,radicle taken from thesolution'is re laced by the continual excess of sulphur oxide gasintroduced or charged into the solution.

My process is a selective process andat tacks only the calcium phosphateand. calcium carbonates. I

Various steps in the process may be made by those skilled in the artwithout departing from the spirit of my invention, as claimed.

I claim: A process of making phosphoric acid comprising subjecting thefinely ground calcium phosphate in the presence of water to sulphurdioxide under pressure the quantity of sulphur dioxide being in excessof that required to" form sulphurous acid with the water. In testimonywhereof I have signed my name to this specification.

HENRY BLUMEN BERG, JR,

